For those seeking a more interesting ascent of Buckskin than the standard Kite Lake routes, the west ridge from Mount Tweto offers a very entertaining alternative. The ridge appears more difficult from afar than it actually is. By and large, the crest can be followed at exposed class 2 with occasional, thought-provoking class 3 downclimbs. The final pitch up Buckskin's rugged west face is fun scrambling on solid rock. Virtually every obstacle on the ridge can be bypassed on the south side via steep talus slopes if you need to cheat. This is a fun ridge and a nice alternative to the standard Mosquito Range walk-ups.
One consideration when undertaking this climb is how to descend. Returning to Mosquito Gulch from Buckskin is very possible but not particularly pleasant due to the steep scree slopes on Buckskin's south side. Either pick your way down this slope or consider a car-to-car shuttle from Mosquito Gulch to Kite Lake (see Kite Lake directions given for the other Buckskin routes).
The westernmost portion of the ridge is the summit of Mount Tweto which is accessed from Mosquito Gulch. Locate Park County Rte 12 approximately 1 mile south of Alma along CO 9. Follow Rte 12 approximately 7 miles to a switchback. Despite earlier warning signs, passenger cars can make it to this point in the road.
From the trailhead, you must first find your way to Tweto's summit. The most direct approach is to follow scattered 4x4 roads or bushwack through willows west into the high basin. The goal is to follow gentle grass and talus slopes to the high saddle between Mount Tweto and Treasurevault Mountain. Once you've attained the ridge, a short hike up easy talus will take you to Tweto's summit. I found that an immediate bushwack through the willows north of the trailhead will rapidly bring you to open grassy slopes that can then be followed west toward the Tweto/Treasurevault saddle.
From Tweto, the final pitch to Buckskin appears imposing. It ends up being much easier than it appears. Head east along the ridge enjoying doubly exposed catwalks on stable blocks. The scrambling is mostly class 2. As you proceed down to the ridge's low point, a few spots of class 3 scrambling will be encountered. Talus slopes to your right offer escape if you are uncomfortable with any of the obstacles. Proceed for 1 mile until you reach the final pitch to Buckskin's western summit. Careful route-finding will yield class 3 scrambling or class 2 talus-hopping through the several cliff bands that make up the face. However, endless 4th and 5th class options exist if you look for them. The rock on the final pitch is awesome quartzy granite with tons of tiny, solid holds. The climbing is steep until it abruptly gives way to the western summit. I'm convinced that this is the true summit but, for thoroughness, continue east along the summit ridge to the supposedly higher eastern summit.
Descend down knee-wrecking scree to Mosquito Gulch or head down the standard route to Kite Lake if running a car shuttle.
Water and food. The ridge is long and route-finding on these kinds of climbs always takes longer than you'd think. During the shoulder seasons, the presence of snow might necessitate an ice ax.
Tour de Mosquito Gulch
For the truly dedicated peak-bagger, consider a loop around Mosquito Gulch. This route collects 7 named or ranked thirteeners and will keep you above 13000' for over six miles. Masochists only!
Ascend London Mountain via its SE face on very steep grass and stable talus. These slopes are obvious avalanche paths that you can see from the road. Follow London's west ridge to UN 13548 (soft-ranked). Turn north and traverse over Mosquito Peak (a bicentennial) and Treasurevault Mtn (soft-ranked) to Mount Tweto (a bicentennial). Follow the Tweto-Buckskin traverse to Buckskin (a centennial) then make your victory lap along easy goat trails to Loveland Mtn (unranked). Descend knee-rattling scree to Rte 12, then return to your car. You've just done 10 miles and over 1 mile of vertical climbing, almost entirely above 13000'!